- Mini-VOX and relay
VOX stands for "voice operated switch". Basically this kit picks up audio via a microphone input, amplifies it and uses it to operate a relay. Sensitivity can be adjusted by an onboard trimpot. Use it to give you hands-free control of things like tape recorders, lights, sirens, etc. Relay contacts rated ar 12/24VDC @ 1A. Based on a circuit published in Silicon Chip, Sep 1994, p31
K142 - 12 Channel Infra-Red Relay Board with remote
This kit comprises the same commercial 14-button IR remote controller as used in K92 PLUS a 12 channel relay board. All 12 relays are provided on the receiver board - nothing more to add. Makes it very simple to add infrared remote control to any project or existing equipment. Indicator LEDs show which relay is operated. Operating range up to 18 metres/60 feet (length of the factory!).
The 12 relays are grouped into 2 groups of 8 and 4. Each group of relays can be set to operate as toggling or momentary. Buttons 1 to 12 on the remote control operate the corresponding relay on the receiver board, ie. button 1 operates relay 1, etc. Buttons 13 and 14 are used to turn off each group of relays.
The relay contacts are rated at 10A max. However the PCB traces will only handle about 5A - additional heavy duty wire will need to be soldered from the relay contact to the screw terminal connector to handle the full 10 amps. The relay outputs are also rated to switch up to 240VAC mains voltages. Extreme care should be taken when switching mains voltage. Don't do this unless you are experienced and know exactly what you are doing. Mains voltages can be lethal!
Receiver board requires a 12VDC 500mA power supply - a suitable AC/DC adaptor will do fine. The remote control unit requires 2 x AAA batteries (not supplied). The receiver board measures 122mm x 113mm (4.8" x 4.45").
Featured in September 2002 issue of Silicon Chip (click for article).
K157v3 - 2 Channel UHF Remote Control with Reset
K157Av3 - 2 Channel UHF Remote Control, Assembled
Two channel version of K180, a 4-channel UHF remote control kit. Two channels have been removed from the K180 receiver board and a 2 button transmitter unit used instead. State of the art unit using 'rolling code' for extra security. Up to 15 transmitters can be linked to one receiver module. See K180 for a full explanation of rolling code.
The latest version (v3) now includes a reset input to each channel when in TOGgle mode. Thus, for example, a garage door motor could be started when the TOGgled relay is activated. Then it will automatically cut off when the door has travelled its full movement and it hits a switch which resets / turns off the corresponding relay.
The pre-built transmitter and receiver/decoder modules are also available as separate items - A17-Tx and A17-Rx.
K173 - RF Data Link Transmitter, Serial Input
K174 - RF Data Link Receiver, Serial Output
K175 - RF Data Link Transmitter, Parallel Input
K176 - RF Data Link Receiver, Parallel Output
These are a series of four kits that implement an RF data link. Each receiver has a 4-bit address set by an onboard 4-way DIP switch. This allows a total of 16 receivers to be used in a 'network' with each one being uniquely addressable.
The RF modules operate at 433.94MHz and use 'amplitude modulation' to transmit data. This transmission method, also know as 'On-Off Keying (OOK)', transmits data by simply switching the carrier signal on and off. The RF transmitter and receiver modules used in these kits are available as separate items, A18-Tx and A18-Rx. They are produced by 'WenShing' of Taiwan - datasheets can be downloaded from their website at "www.wenshing.com.tw".
Each kit contains an Atmel 89C2051 microcontroller that handles all the I/O as well as encoding and decoding the data. The code is NOT available for distribution.
K173 can receive up to 64 characters via its serial port and transmit the message. The serial port baudrate is selectable from 300, 1200, 2400 and 9600. The data format is fixed at 8N1 (8 data bits, no parity, 1 stop bit). Two input modes are available as well as input echo if required. An optional destination address can be automatically inserted into the message before transmitting.
K174 will receive any messages sent by K173 or K175 and output the data via its serial port. The data format is fixed at 8N1 (8 data bits, no parity, 1 stop bit). The data rate is selectable between 2400 and 9600 baud. An optional carriage return/line feed can be appended to the output.
K175 monitors 8 digital inputs for change. If change is detected on any input the state of all the inputs is transmitted. An optional destination address can be added to the message before transmitting. The pinout of the input connector allows direct connection to a PC printer port.
K176 will receive any messages sent by K173 or K175 and output the data via its parallel port. The pinout of the output connector is the same as a PC printer port, allowing direct connection to a printer. Optional features are included to control a Centronics type printer.
A technical manual detailing the technical features and operating guidelines of the four kits is available. You will need to download and read this document to be able to use all the features and options of these kits in your own application.
K180v3 - 4-Channel UHF Relay board with Resets
kit is a modified and improved version of the original K180 kit. It is still
a 4-channel 'rolling code' UHF remote control with the addition of an individual
reset input for each channel when used in toggle mode. For example this makes
it much easier to use the kit for controlling doors or gates when they are fully
opened or closed. By adding limit switches and connecting them to the corresponding
reset input the door or gate will automatically stop when it reaches the end
of its travel.
Assembly is also easier - a single relay driver IC has replaced all the resistors and transistors used in the original circuit. Click here for the original Silicon Chip article.
A 'state of the art' UHF remote control using 'rolling code', almost impossible to 'crack'. Uses a pre-built 'keyfob' style transmitter (as used in many car lock systems) with 4 pushbuttons, one for each relay on the matching receiver board. Each relay can be either latching or momentary in operation. An LED for each relay indicates when it is operated. The receiver board uses a pre-built UHF receiver module to decode the transmitter signal.
Up to 15 transmitter units can be learnt by one receiver unit. Press button 1 on the transmitter while simultaneously pressing the LEARN pushbutton on the receiver board. You only have to do this for less than 1 second. After about 15 seconds the two units will internally connect and recognize each other. Transmitters 'connected' to any receiver unit can be unattached by pressing the LEARN button continuously for 8 seconds.
The transmitter/receiver modules use KEELOQ technology from Microchip to generate the 'rolling codes'. For more information about KEELOQ see AN662 and AN665 from Microchip.
The pre-built transmitter and receiver/decoder modules are also available as separate items - A16-Tx and A16-Rx.
K181 - 10 Channel UHF Remote Control
This kit uses the same Tx/RX pair as K180 but it uses all 10 defined keypress combinations out of the 4 buttons to activate relays. If you read the technical documention the following keypress combinations give readable outputs: pins 1, 2, 3, and 4 (of course) and the pins 1&2, 1&3, 1&4, 2&3, 2&4, and 3&4 pressed together. A PIC16F628 does ALL the work.. A PIC16F628 does ALL the work - source code here.
Toggle or momentary mode is determined by keeping the one or two buttons depressed for more than 2 seconds and then that relay will stay in that mode until another >2 sec keypress. Small relays are used to save weight and board area.
A customer complained that he wanted to hold down buttons for more than 2 seconds and that the software would not let him do it! The reason was that he was controlling variable speed motors: one button up, another down. The firmware was changed to accomodate this.
Now, to change the channel operating modes you now hold ANY key down while powering up the receiver. When you release the key, the indicator LED will begin to flash letting you know that you have entered channel setup mode. Now just hold any of the 10 key channel combinations for the usual 2 seconds to change between ON/OFF or TOGGLE modes.
The indicator LED will flash at a faster rate for a second or so to let you know that the mode has changed. It will then stay off until you release the key(s). You can modify all 10 channels in this way - no need to turn power back off in between setting channels. No relays will operate in channel setup mode.
Once satisfied that the
channel setup is complete, turn the receiver power back off. If NO transmitter
keys are pressed on receiver powerup, then the system is in operational mode,
and the keys will control the relays as per the user setting.
Download the hex file for this mode here. You will have to reprogram the 16F828 chip yourself. Otherwise you can buy one from us.
The pre-built transmitter and receiver/decoder modules are also available as separate items - see A16-Tx and A16-Rx below.
A16-Tx - 4-Button RF Transmitter (as used in K180 & K181)
A16-Rx - 4-Channel RF Receiver module (as used in K180 & K181)
A17-Tx - 2-Button RF Transmitter (as used in K157)
A17-Rx - 2-Channel RF Receiver module (as used in K157)
A18-Tx - RF Data Link Transmitter module, 433MHz
A 433.92MHz transmitter module using ASK modulation with a maximum data rate of 8kbps. Operating voltage is 3-12V. Up to 10mW peak output power, depending on supply voltage. Simple economical solution for many wireless applications.
Typical range is about 100 metres (300 feet) in 'open air' and around 30 metres (100 feet) inside, depending on operating enviroment, supply voltage and antenna. The antenna can be a short wire 17cm (6.7") long (1/4 wavelength).
A18-Rx - RF Data Link Receiver module, 433MHz
Companion receiver module for A18-Tx. ASK modulation with maximum data rate of 4.8kbps and maximum sensitivity of-106dBm. Operating voltage = 5V.